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Electronics => Projects, Designs, and Technical Stuff => Topic started by: edba on April 28, 2020, 06:39:31 pm

Title: Reed switch coil design
Post by: edba on April 28, 2020, 06:39:31 pm

Hi

I have a reed switch (STANDEXMEDER MK23-85-C-2) and I want to wind a coil onto the glass body to be able to operate as a reed relay. The reed switch glass body winding area is 15mm appx x 2.75mm dia winding area. The contacts are specified to close between 15-20AT. I know I had a book years ago explaining how you could wind a coil on the body to operate it. Ideally I would want to operate the reed relay with a 20mA current at 5V. Does anyone know about the calculations involved in working out the number of turns required?

Edba

Title: Re: Reed switch coil design
Post by: langwadt on April 28, 2020, 08:25:08 pm

something along these lines 20AT/20mA = 1000 turns, adjust wire size until you get 5V/20mA  = 250 Ohm

Title: Re: Reed switch coil design
Post by: edba on May 01, 2020, 07:59:29 pm

Hi

Thamks for your reply. I would like to do a bit more reading about this, do you know of a good tutorial on the web? Also do you know of the formula for calculating the length of wire vs no. of turns for thickness of wire. I have done some coil design but not for about 25 years!

Edba